eukaryotes Flashcards
First eukaryotic cells appeared on earth ______ years ago
4 billion
Bacteria and eukaryotes evolved from a precursor called the
Last Common Ancestor (LCA)
o Neither eukaryotic or prokaryotic
o Give rise to bacter
Last Common Ancestor (LCA)
▪ From primitive cells
▪ Trapped in eukaryotic cells
Organelles
is NOT PATHOGENIC. However, once it enters a host that has weak immune system, it becomes an OPPORTUNISTIC microorganism.
Staphylococcus epidermidis
Origin of organelles, such as the mitochondrion and chloroplast, are said to be due to bacterial / archaeal cell parasitizing a descendant of the
LCA
endosymbiosis
The act of protists engulfing each other which results to prokaryotic cells
endosymbiosis
Proteins cannot be created without RNA
endosymbiosis
mitochondria and
chloroplasts have:
o Circular DNA
o 70S ribosomes
o Two-layer membranes
• Can only be passed from the mother
- Happens as the egg cell contains 23 chromosomes
MITOCHONDRIAL DNA
o Found in prokaryotes
o Are present in the matrix of
mitochondria and chloroplast
70S ribosomes
o Found in eukaryotes
80S ribosomes
• Single-celled
• Independent
Firs primitive eukaryotes
• Evolved when cells lost the ability to survive apart from the colony
Multicellular organisms
Has high levels of organization
multicellular organisms
o Group of cells that perform specific
functions
Tissues
o Group of tissues
Organs
If a person gets infected with ______, it stays on its host forever and will remain in its cystic stage.
amebiasis
Cause of amebiasis
shellfish and water
Eukaryotic organism that is always unicellular
protozoa
Eukaryotic organism that may be unicellular / multicellular
fungi and algae
Eukaryotic organism that is always multicellular
helminths (have unicellular egg or larval forms)
FOUND IN ALL EUKARYOTIC CELLS (8)
• Cytoplasmic (cell)
membrane
o A must for
prokaryotes
• Nucleus
• Mitochondria
• Endoplasmic
reticulum
• Golgi apparatus
• Vacuoles
• Cytoskeleton
• Glycocalyx
FOUND IN CELLS OF SOME EUKARYOTES
• Cell wall
• Locomotor
appendages
• Chloroplasts
(plants)
10x thicker than eukaryote
bacterial flagella
Structurally more complex than eukaryotic flagella
bacterial flagella
Covered by an extension of the cell membrane
bacterial flagella
Long, sheathed cylinder containing regularly spaced hollow microtubule
eukaryotic flagella
•Approximately 3 to 4 million species of _____ can be divided into two groups
fungi
: mushrooms, puffballs, and gill fungi
Macroscopic fungi
: molds and yeasts
Microscopic fungi
Round to oval shape
• Uses asexual reproduction
yeast cell
Long, threadlike cells found in filamentous fungi or molds
• Pseudohypha: chain of yeast
hyphae
: chain of yeast
Pseudohypha
• Some fungi can take either form dependent on growth conditions
dimorphic
• Used in winemaking, baking, and brewing since ancient times
• Isolated from skin of grapes
Saccharomyces cerevisiae
• Acquire nutrients from a wide variety of substrates
• All fungi are _____
Heterotrophic
• Obtain substrates from dead plants and animals
Saprobes
• Live on the bodies of living animals or plants
Parasites
the woven, intertwining mass of hyphae that makes up the body or colony of a mold
mycelium
: cross walls dividing hyphae into segments
Septa
: fungal reproductive bodies
Spores
have many complex and successful reproductive strategies
fungi
are responsible not only for multiplication, but also for survival, producing genetic variation and dissemination
Fungal spores
separated piece of mycelium can generate a whole new colony
fragmentation
Primary reproductive mode:
spore formation
• Formed by successive cleavages within a sporangium
Sporangiospores
• Free spores not enclosed by a spore-bearing sac
Conidiospores or Conidia
Important variations occur when fungi of different genetic makeup combine their genetic material
• Slight variations in the form and function are potentially advantageous to the adaptation and survival of the species
sexual spore
caused by environmental pathogens
Community-acquired infections
caused by fungal pathogens in clinical settings
•Hospital-associated infections
caused by pathogens infecting already weakened individuals like transplant, cancer, and HIV-positive patients
Opportunistic infections
•Fungi are involved in other medical conditions besides infections.
• Allergies
• Neurological conditions due to toxin production
t or f
true
penicillin
alexander fleming
•Algae and protozoa have been traditionally combined into the
Kingdom Protista
Two major taxonomic categories:
• Subkingdom Algae
• Subkingdom Protozoa
: any eukaryotic unicellular or colonial organism that lacks true tissues
•Protist
•Group of photosynthetic organisms by their large members such as seaweed and kelp
algae
Widespread inhabitants of fresh and marine water
algae
• Floating community of microscopic organisms
• Essential role in the aquatic food web
• Produce about 70% of the earth’s oxygen
•Primary medical threat from algae is through ingestion of toxins during a red tide (Paralytic shellfish Poisoning)
plankton
The protozoa include about 65,000 species
• Predominant habitats for protozoa are fresh and marine water, soil, plants, and animals
• While most members are harmless, a few species are parasites responsible for hundreds of millions of infections in humans per year
protozoa
• Scavenge dead plant or animal debris
• Graze on live cells of bacteria and algae
Free-living species:
• Live on fluids of the host such as plasma and digestive juices
• May actively feed on tissues
Parasitic species:
• Amoeboid motion
• Serve as feeding structures
Pseudopods (“false feet”):
• Vary in number from one to several
Flagella
• Distributed over the entire surface of the cell in characteristic patterns
•Cilia
• Motile feeding stage
• Requires ample food and moisture to remain active
Trophozoite
• Dormant, resting stage
• Formed when conditions become unfavorable for growth and feeding
• Important factor in the spread of disease
Cyst
form of genetic exchange between two cells
Conjugation
: study of protozoa and helminths
Parasitology
: term most often used to denote protozoan and helminth pathogens
Parasite
: sleeping sickness in Africa
Trypanosoma brucei
: Chagas disease; endemic to South and Central America
Trypanosoma cruzi
: thin, often segmented body plan
Flatworms
• Divided into cestodes
(tapeworms) and trematodes (flukes)
flatworms
: long, cylindrical, unsegmented body
Roundworms (also called nematodes)
host in which adulthood and mating
occur
Definitive (final) host
: sexes have different morphologies
Nematodes
: sexes are separate or male and female sex organs in the same worm (hermaphroditic)
Trematodes
affects almost 240 million people worldwide, and more than 700 million people live in endemic areas. The infection is prevalent in tropical and sub-tropical areas, in poor communities without potable water and adequate sanitation.
Schistosomiasis
• Causes a very common infestation of the large intestine
• Worms range from 2 to 12 mm long
• Tapered, curved cylinder shape
• Simple, uncomplicated infection that does not spread beyond the intestine
Enterobius vermicularis
